Device for branching off a fluidic partial flow

ABSTRACT

The invention relates to a device for branching a fluidic partial flow off a main flow by means of a hydraulic pump ( 10 ), said device comprising individual main chambers ( 12,14,16,18,20 ) which are sealed from each other and divided into functional groups, and operate according to the displacement principle. Said chambers enable fluid from at least one main flow inlet ( 22 ) to be transported from an inlet or suction side to an outlet or pressure side of the hydraulic pump ( 10 ) and then via at least one main flow outlet. At least one independent partial chamber ( 26 ) is provided for the transport of the partial flow, in addition to the main chambers ( 12,14,16,18,20 ), said partial chamber forming part of the pressure side of the hydraulic pump ( 10 ) and being connected to an independent partial current outlet ( 42 ) separate from the respective main flow inlet ( 22 ) and the respective main flow outlet ( 24 ).

The invention relates to a device for branching off a fluidic partialflow from a main flow by means of a hydraulic pump which, workingaccording to the displacement principle, has individual main chamberswhich are sealed off from one another, which are divided into functionalgroups, and by means of which fluid coming from at least one main flowinlet can be transported from the inlet side or suction side to theoutlet side or pressure side of the hydraulic pump and further by way ofat least one main flow outlet.

Hydraulic pumps (DE 21 14 202 C3) of this type are known in the priorart in a plurality of embodiments. Generally, hydraulic pumps are usedto convert mechanical energy in the form of torque and rotational speedinto hydraulic energy with a definable volumetric flow and fluidpressure. Hydraulic pumps which work according to the so-calleddisplacement principle have individual chambers which are sealed in thepump housing, in these chambers fluid being transported from the inletside of the pump, comprising a suction port, to the outlet side in theform of the pressure port. Since in this respect there is no directconnection between the suction port and the pressure port, pumpsaccording to the displacement principle are suitable especially for highfluid system pressures.

Depending on whether vanes or pistons are used for implementation of thedisplacement principle, gear pumps and spiral pumps are distinguishedfrom the vane pumps as dictated by design and the latter in turn fromthe radial and axial piston pumps. It is common to all these pumps thatregardless of whether the displacement volume is kept constant orvariable, the displaced volume certainly always relates only to a fluidflow which is to be delivered and which is hereinafter referred to asthe main flow.

Proceeding from this prior art, therefore, the object of the inventionis to further improve the known solutions such that the range ofapplication of these devices with a hydraulic pump is expanded in acost-effective manner. This object is achieved by a device with theentirety of the features of claim 1.

The device according to the invention enables the branching off of afluidic partial flow from the indicated main flow, for the transport ofthe partial flow at least one independent partial chamber in addition tothe main chambers being designed for conveyance of the main flow, whichpartial chamber is a component of the pressure side of the hydraulicpump and is connected to an independent partial flow outlet which isseparated from the respective main flow inlet and the respective mainflow outlet.

The branched-off partial flow from the main flow makes it possible touse the partial flow for the most varied tasks, both the fluid volume ofthe partial flow and also its fluid pressure being definable dependingon the design of the device. This fluidic partial flow can therefore beused independently of the main flow for the supply of individual fluidicconsumers. Emergency supply of hydraulic components in the field of rollstabilization or emergency supply of steering assist systems in case offailure is also easily possible via the partial flow. Furthermore, thepartial flow which is branched off from the main flow can be subjectedto sensor checking, for example, can be analyzed for the degree of itsfouling in order in this way to obtain qualitative information about themain flow. Here, a plurality of applications in the most varied areas ispossible.

In one especially preferred embodiment of the device according to theinvention, it is provided that the hydraulic pump is a vane pump.Preferably, the individual vanes of the vane pump are guided in adrivable rotor to be able to move lengthwise between an end position inthe rotor and an enclosing wall of a stator, which wall limits thetravel of the vanes to the outside such that for at least one part ofthe vanes, two opposite fluid spaces at a time between the latter andthe rotor and the stator are formed. As a result of the opposite fluidspaces, depending on their volumetric configuration for differentapplications, different pressure levels can be implemented by means ofone device; this also leads to further possibilities of adaptation torequirements of the hydraulic circuit for the main flow.

The device according to the invention, however, need not be limited touse in a vane pump, but essentially all hydraulic pumps can be used herewhich work according to the displacement principle or a comparableprinciple.

The device according to the invention for partial flow formation withoptionally definable volumetric portion, depending on the design of thedevice, is preferably made as a module which can be combined with othercomponents such as, for example, drive units and/or filter units, withthe formation of integral fluidic devices, but can also be used as anindividual module in complete systems such as for roll stabilization,steering support, etc., where independent partial volumetric flows arerequired for diverse control tasks, but also for emergency functions.

Other advantageous embodiments of the device according to the inventionare the subject matter of the other dependent claims.

The device according to the invention is detailed below using oneexemplary embodiment. The figures are schematic and not to scale.

FIG. 1 shows, in the form of a longitudinal section, the essentialcomponents of the device according to the invention, the bottom edge ofthe figure being shown partially cut off for the sake of simplicity;

FIG. 2 shows, in the form of an exploded diagram, the subject matter asshown in FIG. 1, but in a plane of the figure offset thereto;

FIG. 3 shows a face-side bottom view of the chamber block as shown inFIGS. 1 and 2;

FIG. 4 shows one possible application example for the device shown inFIGS. 1 to 3.

The device which is shown in FIGS. 1 to 3 is used for branching off afluidic partial flow from a main flow by means of a hydraulic pump 10which, working according to the displacement principle, has individualchambers 12, 14, 16, 18, and 20 which are sealed off from one another,and by means of which fluid can be transported from the inlet side orsuction side to the outlet side or pressure side of the hydraulic pump10.

For the partial flow to be branched off, there is an independent partialchamber 26 which is a component of the pressure side of the hydraulicpump 10 together with the third chamber 16, the fourth chamber 18, andthe fifth chamber 20, whereas the first chamber 12 and the secondchamber 14 are assigned to the suction side.

In the present case, the hydraulic pump 10 is a vane pump whosedirection of rotation is shown with an arrow 28 in FIG. 3. Theindividual vanes 30 of the vane pump are guided in a drivable rotor 32to be able to move lengthwise between an end position in the rotor 32and an enclosure wall 34 of a stator 36, which wall limits the travel ofthe vanes 30 to the outside such that for the vanes 30 two oppositefluid spaces 38, 40 at a time are formed between them and the rotor 32and the stator 36.

As further follows from FIG. 3, viewed in the direction of rotation, theright fluid space 38 and the fluid spaces 40 widen and thus apply asuction action to the main fluid volumetric flow with inclusion of theindividual chambers 12 and 14. Conversely, viewed in the direction oflooking at FIG. 3, in the direction of rotation of the vane pump, thefluid spaces 38 and 40 taper relative to the chambers 16, 18, and 20 sothat the main flow travels to the outlet side or pressure side with adefinable pressure level. This displacement principle is known inconnection with vane pumps and comparable positive displacement pumps sothat it will not be further detailed here. But as a result of theindividual chambers together with the fluid spaces 38 and 40 both on thesuction side and also on the pressure side for the individual chambers12 relative to 14 as well as 16 and 18 relative to 20, a differentpaired pressure level can be set so that two main flows separated fromone another could be triggerable by means of the device. In thisexemplary embodiment, however, only one main fluid flow is conveyedjointly with the chambers 12, 14, 16, 18, and 20.

To form the fluidic partial flow, the partial chamber 26 is used whichis separated in space from the other indicated chambers and has aseparate partial flow outlet 42. The partial flow quantity is dischargedvia the indicated partial flow outlet 42 and is pushed out of the deviceby the respective vane 30 in the travel direction to the second fluidspace 40. Since the vanes 30 cross the partial chambers 26 in directsuccession, fluid is permanently discharged to the outside on thepressure side of the device via the partial flow outlet 42. In thisexemplary embodiment, after supplying a hydraulic consumer, forperforming an emergency function, or after passing through a sensor unit(not shown), the partial flow is brought to the suction side of thedevice and in turn delivered to the device via the partial flow inlet44.

Overall, it remains to be stated that one part of the fluid spaces 38,40 is assigned to the individual chambers 12, 14, 16, 18, and 20 of thesuction side and the pressure side of the hydraulic pump 10 and thatanother part, formed by at least one of the fluid spaces 40, is assignedto the partial chamber 26 for partial flow formation. As the explodeddrawing in FIG. 2 shows in particular, the stator 36 is formed from ahollow cylindrical ring which can be accommodated in a housing 46 of thedevice. The rotor 32 with its individual vanes 30 is held eccentricallywith its drive axis in the stator 36 for purposes of implementing thealready described vane pump principle. The illustrated chambers 12, 14,16, 18, 20, and 26 are in turn a component of an independent chamberblock 48, for the sake of simplicity the fourth chamber 18 not beingshown in FIG. 2. The chamber block 48 ends to the outside flush with thedevice housing 46 (compare FIG. 1) and is sealed accordingly to theinside in the direction of the stator 36 by way of a gasket 50. There isanother gasket 52 on the side opposite the chamber block 48 for sealingof adjoining parts of the device.

For driving the vane pump, a drive shaft 54 is used which is sealed tothe outside by a chambered gasket 56, and by an independent gasket 58relative to a drive shaft 60 of an electric motor 62 (compare FIG. 4).As illustrated in FIG. 2, the partial flow outlet 42 is shown offset inthe plane of the figure by a pivot angle of approximately 120° comparedto FIG. 1.

As the figures furthermore show, the chambers 12, 14, 16, 18, and 20discharge from the suction side 22 and the pressure side 24 within thechamber block 48 to its two opposite face sides 64, 66 into theenvironment, except for the partial chamber 26 for partial flowformation which on its side facing away from the hydraulic pump 10 isclosed to the outside by wall parts 68 of the chamber block 48 (FIG. 1).Furthermore, the individual chambers 12, 14, 16, 18, and 20 as well as26 are arranged running in a concentric configuration to the drive axle(drive shaft 60) of the hydraulic pump and are otherwise madesickle-shaped. The first chamber 12 with the third and fourth chambers16 and 18 forms the outer concentric ring, and the second chamber 14with the fifth chamber 20 and the partial chamber 26 lies on the innerconcentric circular path around the drive axis. If other positivedisplacement pumps were to be used for the hydraulic pump 10, adifferent arrangement must be chosen, for separating the partial flowfrom the main flow an independent branch chamber being necessary forthis purpose with a separate outlet relative to the inlets and outletsfor the main flow.

One exemplary embodiment for the application of the described device isshown below based on FIG. 4. Here, the device shown in FIGS. 1 and 3 isseated on a filter unit which is designated as a whole as 70 and whichis of conventional design. The filter unit 70 has a replaceable filterelement 72 in a filter housing 74, the filter mat 76 of the filterelement 72 on the inner peripheral side being supported by aconventional support pipe 78 with inside walls 80 which are arranged ina star-shape. Furthermore, the filter unit 70 on its top has a fluidinlet 82 and a fluid outlet 84 which route the main flow. Furthermore,the filter unit 70 has a bypass device which is designated as a whole as86 and which directly clears the fluid path between the device accordingto the invention and the fluid outlet 84 if the filter element 72 isblocked as a result of dirt.

Opposite the filter unit 70 and seated from above on the deviceaccording to the invention, there is the electric motor 62, wherein, forthe sake of simplicity, the electrical winding has been omitted. Theelectric motor 62 drives the drive shaft 60, which viewed in thedirection of looking at FIG. 4 engages the rotor 32 of the vane pumpwith its bottom end in order to ensure its driving in this way. If thevane pump is being operated as a hydraulic pump 10, it intakes fluid viaits suction side and therefore via a main flow inlet 22 via the fluidinlet 82. On the pressure side and therefore via the main flow outlet24, the pertinent amount of fluid of the main flow is delivered via apassage site 88 (compare FIG. 1) into the fluid space 90 between thefilter housing 74 and filter element 72. After flowing through thefilter element 72 from the outside to the inside via the wall guide ofthe support pipe 78, the cleaned fluid is routed out of the device viathe fluid outlet 84. At the same time, in this delivery operation forthe main flow, secondary flow fluid is intaken via the partial flowinlet 44, for example, originating from a sensor device, and via theseparate partial chamber 26 and the partial flow outlet 42 in turnrelayed to the sensor device (not shown), for example, for determiningthe degree of fouling of one part of the fluid of the main flow.

The above described exemplary embodiment is only exemplary, and thedevice according to the invention can be used wherever a partial flowamount is required from a main flow. In this way, emergency functions inroll stabilization devices in the motor vehicle and/or steering assistdevices can also be provided with partial flow fluid.

1. A device for branching off a fluidic partial flow from a main flow by means of a hydraulic pump (10) which, working according to the displacement principle, has individual main chambers (12, 14, 16, 18, 20) which are sealed off from one another, which are divided into functional groups, and by means of which fluid coming from at least one main flow inlet (22) can be transported from the inlet side or suction side to an outlet side or pressure side of the hydraulic pump (10) and further by way of at least one main flow outlet (24), characterized in that for the transport of the partial flow at least one independent partial chamber (26) in addition to the main chambers (12, 14, 16, 18, 20) is provided which is a component of the pressure side of the hydraulic pump (10) and is connected to an independent partial flow outlet (42) which is separated from the respective main flow inlet (22) and the respective main flow outlet (24).
 2. The device according to claim 1, characterized in that the hydraulic pump (10) is a vane pump.
 3. The device according to claim 2, characterized in that the individual vanes (30) of the vane pump are guided in a drivable rotor (32) to be able to move lengthwise between an end position in the rotor (32) and an enclosing wall (34) of a stator (36), which wall limits the travel of the vanes (30) to the outside such that for at least one part of the vanes (30) two opposite fluid spaces (40, 38) at a time are formed between the latter and the rotor (32) as well as the stator (36).
 4. The device according to claim 1, characterized in that on the suction side (22) and the pressure side (24) of the hydraulic pump (10) there are at least two chambers (12, 14; 16, 18, 20, 26) in one chamber block (48) of the device and that one part of the chambers (12, 16, 18) can be assigned to the one fluid space (38) and the other part of the chambers (14, 20, 16) can be assigned to the other fluid space (40) of each vane (30).
 5. The device according to claim 4, characterized in that the chambers (12, 14, 16, 18, 20) discharge from the suction side and the pressure side within the chamber block (48) to its two opposite face sides (64, 66) into the environment and that the partial chamber (26) for partial flow formation on its side facing away from the hydraulic pump (10) is closed to the outside.
 6. The device according to claim 1, characterized in that the individual chambers (12, 14, 16, 18, 20, 26) are made sickle-shaped and running in a concentric arrangement to the drive shaft (60) of an electric motor (62).
 7. The device according to claim 1, characterized in that the partial flow branched off from the main flow on the pressure side of the hydraulic pump (10) can be supplied to a hydraulic consumer, preferably in the form of a sensor device, after passage through which the partial flow returns to the suction side of the hydraulic pump (10).
 8. The device according to claim 6, characterized in that the electric motor (62) is used for driving the hydraulic pump and that for filtration of the fluid of the main flow there is a filter unit (70) which can be connected on opposite sides to the device as part thereof. 